src attribute of the script tag (XHTML 1.1)

The src attribute of the script tags allow you to include an external file and have it interpreted along with the current document. This allows you to have large quantities of scripting code placed elsewhere, so that it doesn't clutter up your HTML files. Here's an example, where we include a JavaScript file from the same directory, into our page:

<script type="text/javascript" src="javascript.js"></script>

You can refer to variables, functions etc. from the external file as if they were written directly in the script block.